Fuel line

ABSTRACT

The present invention refers to a fuel line for conveying fuel from and/or into a fuel tank. To suggest a fuel line for conveying fuel from and/or into a fuel tank (tank line), which can be processed easily and shows good mechanical properties and also a high chemical resistance, it is provided according to the invention that the fuel line consists essentially of F-TPV.

The present invention refers to a fuel line for conveying fuel from and/or into a fuel tank.

Tank lines, particularly in-tank lines, are employed in fuel tanks for automotive vehicles and are used for conveying fuel from the tank to the fuel pump. Due to this special use, the demand is made on the tubes or lines that both the inside and the outside must be made resistant to fuel. Moreover, a time- and cost-saving assembly is desired.

Publication EP 1 443 205 A discloses an arrangement comprising such a line. The line serves to connect two tank sections, which are not interconnected because of the saddle type design. Due to the permanent discharge of fuel out of the one portion of the fuel tank, fuel is permanently sucked out of the other part via the tank line. For an easier laying operation the line comprises a plurality of flexible bending sections of a bellows-like structure.

A fuel line that is highly resistant to aggressive media from the outside and also shows a high resistance to fuels on the inside is described in EP 1 635 101 A. To be able to meet this demand, the line has a complex structure consisting of five layers, including three main layers and two bonding layers, one main layer being formed as an intermediate layer of PA 6.

EP 1 942 296 A shows a fluid line used for hydrocarbon-containing pressurized fluids. Due to the mechanical properties that are in the foreground with this application, said line is made from PA 6.10. Especially the processing speed during extrusion is relatively high and is about 20 m/min and thus particularly economic. However, it has been found in practice that PA-based materials cannot be exposed to fuel impact all the time.

It is therefore the object to suggest a fuel line used for conveying fuel from and/or into a fuel tank (tank line) that can be processed easily and shows good mechanical properties and also a high chemical resistance.

To achieve the aforementioned object, the invention provides the fuel line for conveying fuel out of and/or into a fuel tank according to claim 1, wherein the fuel line consists essentially of F-TPV. The material F-TPV comprises a thermoplastic matrix of a fluorothermoplast as the continuous phase, having dispersed therein dynamically vulcanized elastomer particles of fluororubber, wherein the vulcanized domains form the soft phase. For instance ethylene tetrafluoroethylene (ETFE), ethylene-fluorinated ethylene-propylene (EFEP), fluorinated ethylene-propylene (FEP), ethylene chlorotrifluoroethylene (ECTFE), etc. may be used. Copolymers and terpolymers of vinylidene fluoride (VDF), tetrafluoroethylene (TFE) and hexafluoropropylene (HFP) are suited as fluororubber, with a content of 10-60% by wt., depending on the desired product property (module, stiffness/flexibility), at a fluorine content of about 66%-71%, wherein the corresponding product properties can vary within wide limits. In tests the material has turned out to be highly resistant to fuels of the most different types and qualities. In contrast to conventional approaches, which particularly regard multilayered tubes, it is possible to considerably simplify not only the manufacturing process, but also the disposal of the fuel line according to the invention for the reason that substantially only one single material must be provided, processed and later also disposed of, which turns out to be advantageous economically and above all ecologically. Especially in a fully fuel-surrounded state (in-tank application) on the face the fuel line according to the invention can be designed to be resistant to fuels of the most different types and qualities, so that the risk of delamination is considerably reduced.

It can turn out to be advantageous when the fuel line consists of more than 90% by wt., preferably of more than 95% by wt., preferentially of more than 99% by wt, of F-TPV. If the amount of a material differing from F-TPV is less than 10%, the risk of a functional failure of the fuel line is minimal even if it is permanently exposed to aggressive fuels. A certain amount of a material differing from F-TPV could even be desirable, e.g. in order to reduce the overall costs of the fuel line or to equip the fuel line with specific functional sections.

It may turn out to be helpful when the fuel line is configured in a single layer as an F-TPV monotube. The fuel line comprises a single layer extending continuously from the inner periphery to the outer periphery of the fuel line, which layer consists of 100% of F-TPV. With such a design of the fuel line the manufacturing process turns out to be particularly simple. Moreover, the fuel line with this type of design is without any layer boundaries owing to the monolayer structure and thus also without any weak spots with respect to delamination.

It may turn out to be useful when the fuel line is configured at least sectionwise as a plain tube. Plain tube sections are particularly stable and resistant to kinking due to the constant cross-sectional shape. It may be desirable to provide the fuel line at suitable places with plain tube sections so as to prevent, for instance, a reduction of the line cross-section through which fluid can flow, which reduction is e.g. caused by kinking of the fuel line.

It has turned out to be convenient when the fuel line is configured at least sectionwise as a corrugated tube. On account of corrugated tube sections the fuel line can be made highly flexible in a selective way and at the same time highly resistant to kinking, so that the fuel line can even extend along strongly curved lines without the risk of a reduction of the line cross-section through which fluid can flow, which is e.g. caused by kinking of the fuel line.

A preferred aspect of the invention refers to a fuel tank comprising a fuel line according to any one of the preceding designs, the fuel line being positioned at least sectionwise within the fuel tank. With such a so-called in-tank application the advantages of the fuel line according to the invention become particularly clearly apparent because fuel acts on both the inner periphery and the outer periphery of the fuel line.

It may turn out to be advantageous when the fuel line ends in the fuel tank. In this configuration the advantages of the fuel line according to the invention become even more clearly apparent. Especially on the face, the inner layers of a multilayered fuel line are bound to be exposed to the fuel so that in the multilayered fuel line there is always the risk of delamination emanating from the boundary layers. Since the fuel line according to the invention is however essentially made of F-TPV, which is highly resistant to fuels of the most different types and qualities, a delamination of the fuel line can also and above all be prevented whenever the face of the fuel line is exposed to fuel.

It may turn out to be helpful when the material F-TPV is exposed on the inner periphery, on the outer periphery and/or on the face of the fuel line. With this design there are no weak spots on the parts of the fuel line on which the fuel acts and from which a delamination of the fuel line might ensue.

It may turn out to be advantageous when the fuel line extends, starting from a connection of the tank wall, into the fuel tank. Particularly inside the tank it is useful when the fuel line consists of 100% of F-TPV and the material F-TPV is exposed on the inner periphery, on the outer periphery and on the face of the fuel line because the fuel acts on the inner periphery, on the outer periphery and on the face of the fuel line.

It may turn out to be convenient when a further fuel line extends, starting from a connection on the tank wall, outside of the fuel tank, the further fuel line comprising at least one inner layer of F-TPV. Outside the tank, in cases where the fuel is passed in the interior of the fuel line to a fuel pump, or the like, it suffices that the material F-TPV is only exposed on the inner periphery because the fuel only acts on the inner periphery of the fuel line, but not on the outer periphery or the face of the fuel line, so that the risk of delamination of the fuel line emanating from the face does not exist. The single-layer F-TPV monotube made from solid material is perhaps more expensive than a fuel line with only one inner layer of F-TPV, so that a division of the fuel line on the tank wall seems to be quite reasonable for saving costs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a fuel line according to the invention.

FIG. 2 is a schematic view of a fuel tank according to the invention with the fuel line according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a perspective view of the fuel line 1 according to the invention, which is particularly provided for conveying fuel from and/or into a fuel tank. The fuel line 1 according to the invention is characterized in that it consists essentially of F-TPV, which means within the scope of this invention that the fuel line 1 consists of more than 90% by wt., preferably more than 95% by wt., preferentially more than 99% by wt., of F-TPV. It is particularly preferred when the fuel line 1 consists of 100% by wt. of F-TPV and is configured in a single layer as an F-TPV monotube. However, small fractions of other materials may also be present, for instance in order to provide the fuel line 1 with different functional sections, such as connections, markings, couplings, etc. It is important that the fuel line 1 is not in a position to delaminate, particularly owing to the material F-TPV which is very resistant to the most different fuels, whereby the risk of functional failures is considerably reduced.

The material F-TPV for the tank applications described within the scope of this invention comprises a thermoplastic matrix of a fluorothermoplast, such as ethylene tetrafluoroethylene (ETFE), ethylene-fluorinated ethylene-propylene (EFEP), fluorinated ethylene-propylene (FEP), ethylene chlorotrifluoroethylene (ECTFE), etc. as the continuous phase, having dispersed therein vulcanized elastomer particles of fluororubber (FPM), wherein the vulcanized domains of FPM form the soft phase. Copolymers and terpolymers of vinylidene fluoride (VDF), tetrafluoroethylene (TFE) and hexafluoropropylene (HFP) are suited as fluororubber (fluorine content of 66%-71%), with a content of 10-60% by wt., depending on the desired product property (module, stiffness/flexibility, and the corresponding product properties may vary within wide limits).

The fuel line 1 shown in FIG. 1 is formed over the whole length between two faces 10 in a single layer as an F-TPV monotube and comprises one single layer that is continuously extending from the inner periphery Ui to the outer periphery Ua and consists of 100% of F-TPV, so that the material F-TPV is exposed on the inner periphery Ui, on the outer periphery Ua, and on the faces 10 of the fuel line 1. Since there are no layer boundaries whatsoever, there is also no risk of delamination. Moreover, the fuel line 1 comprises a corrugated tube section 11 arranged between two plain tube sections 12. Depending on the desired flexibility, the fuel line 1 can be configured at least sectionwise as a plain tube and at least sectionwise as a corrugated tube. An outer diameter of the fuel line 1 is e.g. between 5 mm and 20 mm, preferably between 8 mm and 12 mm, preferentially 10 mm. A wall thickness of the fuel line 1 is e.g. between 0.5 mm and 5 mm, preferably between 1 mm and 3 mm, preferentially 2 mm.

FIG. 2 shows a fuel tank 2 according to the invention with a fuel line 1 of the invention particularly positioned on the inside, which is configured in a single layer as an F-TPV monotube. Starting from a connection 3 on the tank wall 20, the fuel line 1 extends into the fuel tank 2 and ends in the fuel tank 2. Starting from the connection 3 on the tank wall 20, a further fuel line 4 extends outside of the fuel tank 2 to a fuel pump (not shown), the further fuel line 4 comprising an inner layer of F-TPV and the remaining layers of said fuel line 4 being made of a material differing from F-TPV. The fuel line 4 need not be made of F-TPV solid material because the fuel outside the fuel tank 2 acts neither on an outer periphery nor on the faces of the fuel line 4 in a direct way. 

1. A fuel line for conveying fuel from and/or into a fuel tank, wherein the fuel line consists essentially of F-TPV.
 2. The fuel line according to claim 1, wherein the fuel line consists of more than 90% by wt., preferably of more than 95% by wt., preferentially of more than 99% by wt., of F-TPV.
 3. The fuel line according to claim 1, wherein the fuel line is configured in a single layer as an F-TPV monotube.
 4. The fuel line according to claim 1, wherein the fuel line is formed at least sectionwise as a plain tube.
 5. The fuel line according to claim 1, wherein the fuel line is configured at least sectionwise as a corrugated tube.
 6. A fuel tank comprising a fuel line according to claim 1, wherein the fuel line is positioned at least sectionwise within the fuel tank.
 7. The fuel tank according to claim 6, wherein the fuel line ends in the fuel tank.
 8. The fuel tank according to claim 6, wherein the material F-TPV is exposed on an inner periphery (Ui), on an outer periphery (Ua), and/or on a face of the fuel line.
 9. The fuel tank according to claim 6, wherein the fuel line extends, starting from a connection on the tank wall, into the fuel tank.
 10. The fuel tank according to claim 6, wherein a further fuel line extends, starting from a connection on the tank wall, outside of the fuel tank, the further fuel line comprising at least one inner layer of F-TPV.
 11. The fuel line according to claim 2, wherein the fuel line is configured in a single layer as an F-TPV monotube.
 12. The fuel line according to claim 11, wherein the fuel line is configured at least sectionwise as a corrugated tube.
 13. A fuel tank comprising a fuel line according to claim 12, wherein the fuel line is positioned at least sectionwise within the fuel tank.
 14. The fuel tank according to claim 13, wherein the material F-TPV is exposed on an inner periphery (Ui), on an outer periphery (Ua), and/or on a face of the fuel line.
 15. The fuel tank according to claim 14, wherein the fuel line extends, starting from a connection on the tank wall, into the fuel tank.
 16. The fuel tank according to claim 15, wherein a further fuel line extends, starting from a connection on the tank wall, outside of the fuel tank, the further fuel line comprising at least one inner layer of F-TPV. 